The present invention relates to a probe apparatus.
During the process of fabricating a semiconductor device, after IC chips have been completed on a semiconductor wafer, the wafer is divided into individual chips which are then packaged. At this point, a probe apparatus and tester are used to perform electrical measurements on each of the chips on the wafer, to identify and exclude defective chips before they are packaged.
With a conventional probe apparatus, as shown in FIGS. 12 and 13, a probe card 12 provided with probe pins 11 arrayed to correspond with the electrode pad array of an IC chip on the wafer is placed above a wafer holding table 1 that is movable in the X, Y, Z, and .theta. directions. After the wafer holding table 1 has been moved so that the probe pins 11 have been positioned (aligned) to match the electrode pads of the IC chip on the wafer, the probe pins 11 and the electrode pads are brought into contact, the electrode pads are then brought into electrical contact with a tester head 15 through the probe pins 11 and a contact ring 14 that includes components such as pogo pins 13, electrical measurements such as those using high frequencies to correspond to the usage speed of the IC chip are performed, and thus the electrical connections of the IC chip are determined to be good or not.
In order to perform accurate electrical measurements on the IC chip, the probe pins 11 must be brought into secure contact with the electrode pads, and, to enable this contact, the electrode pads of the IC chip on the wafer W must be accurately positioned with respect to the probe pins 11. Since there are large numbers of circuit components and wiring built into the tester head 15, it is extremely difficult to provide a TV camera therein and move the wafer holding table 1 below the probe pins 11 to position the electrode pads. Therefore an optical unit 17 is placed at a position 16 separated from the tester head 15, and the wafer is positioned below the optical unit 17 by moving the wafer holding table 1 in the X and Y directions, and the wafer W is positioned in the X, Y, and .theta. directions by adjusting the position of the wafer holding table 1 while looking at the electrode pads through the optical unit 17.
The above positioning is performed at four equidistant places around the periphery of the wafer W, as shown for example by the broken lines in FIG. 13, and thus a wide area is required as movement region for the positioning of the wafer holding table 1, within the regions shown by the broken lines. The tester head 15 is also big, so when the optical unit 17 that includes the TV camera is placed at a position separated from the tester head 15 and enough space for positioning below it is ensured, there is the problem that the probe apparatus becomes extremely big. And, since the movement stroke of the probe apparatus is large, there is the problem that highly accurate positioning is difficult.